In an email to about a dozen journalists, Barrett Brown said his Project PM had uncovered the nature of the U.S. spying operation known as Romas/COIN and its replacement called Odyssey.

"For at least two years, the U.S. has been conducting a secretive and immensely sophisticated campaign of mass surveillance and data mining against the Arab world, allowing the intelligence community to monitor the habits, conversations, and activity of millions of individuals at once," Brown wrote.

Brown's team made the discovery by analyzing 70,000 emails from data intelligence firm HBGary Federal. Anonymous stole the emails after HBGary CEO Aaron Barr told the Financial Times that his company had identified "core leaders" of the hacktivist group.